1. Field of the Invention
The present invention relates to a button suitable for a garment of a thick and strong fabric such as jean or denim, and more particularly to a button including a button body and a tack member adapted to be joined with the button body when attaching the button to the garment fabric.
2. Description of the Prior Art
A known button of the mentioned type, as disclosed in Japanese Patent Post-Examination Publication No. 51-10149 and illustracted here in FIG. 5 of the accompanying drawings, comprises a button body A' and a tack member B' adapted to be joined with the button body A' when attaching the button to a garment fabric F'. For attachment, a shank of the tack member B' is caused to pierce through the garment fabric F' and is then inserted into a hollow hub of the button body A' so as to deform or bend a tapering end of the shank, thus securing the shank to the hollow hub of the button body A'. The hollow hub of the button body A' is in the form of a double tube composed of concentric inner and outer tubes 3', 1' integrally joined at their rear or lower ends by an annular bottom portion 2' which is disposed against the garment fabric F' when the button body A' and the tack member B' are joined together. Since the inner and outer tubes 3', 1' are formed in a single integral piece from a sheet of metal, the height H' of the hollow hub of the button body, i.e. the distance between the lower surface of an annular top flange 6' of the button back and the lower surface of the annular bottom portion 2' of the hollow hub, is constant.
Having the constant-height hollow hub, the prior art button would be difficult or sometimes impossible to be fastened in a button hole of the garment if the garment fabric is thicker than usual. At that time, if the button head is forcibly threaded through the button hole, the garment fabric would be broken at portions around the button hole, thus impairing the fastening function of the button. Further, if the garment fabric F' is thinner than usual, a gap would remain between the lower surface of the annular top flange 6' of the button back and the upper surface of the garment fabric F' when the button head is threaded through the button hole, thus causing inadequate fastening function of the button.
Button makers have hitherto coped with this problem by supplying buttons of different heights to meet garment fabrics of different thickness, which would however result in an increased cost of production.